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741.
Luis Antonio Bojórquez-Tapia Peter F. Ffolliott D. Phillip Guertin 《Environmental management》1990,14(3):317-324
The current Mexican environmental law provides the legal basis for comprehensive land-use planning. Under the law, development
of natural ecosystems must combine goals, policies, and practices towards the sustainable use of natural resources and the
protection of biological diversity. Thus, ecosystem manipulation must be able to counter fragmentation of natural ecosystems
and isolation of natural reserves, while providing for human needs. Assessment of the potential of natural ecosystems and
management impacts are required. Multiple-resource simulation is an assessment and land-use planning tool that permits managers
and decision makers to comply with the law, providing a flexible, user-oriented system that can meet the needs of managers,
conservationists, and researchers. A multiple-resource model and an example of how it can be applied to meet planning needs
is presented for discussion. 相似文献
742.
Integrated assessments (IAs) and integrated assessment models (IAMs) arerecent responses to the inter-disciplinary challenges provided by complexglobal environmental issues such as atmospheric change. This paper discussesan array of integrated assessments, providing an overview of the role of IAsas bridges or foundations for epistemic communities. Formal as well associal, political, and ethical issues are presented. As well as a definition of anIA and an IAM, different forms and approaches of current or proposed IAsare reviewed. Particular stress is laid on the need to maintain the integrity ofthe diverse components of an IA. Finally, reference is made to the need tounderstand the underlying ethical and normative concerns that have promotedthe current interest in IA. 相似文献
743.
尤其在判断气候变化可能带来的影响时,事实证明有必要对受到显著的外部影响的有限海域的水更新速度进行评估.随SWECLIM项目一起,上述工作已在波罗的海的两个生态敏感的次盆地(即里加湾和格但斯克湾)中开展.为此目的,我们已分别以质量平衡收支和拉格朗日轨迹线为基础,采用了两种方法上不同的做法.与采用拉格朗日技术获取的结果相比,事实证明,在作为一个在形态上受到极大约束的盆地的里加湾中,使用这种箱状模型方法非常合适,而在将它用于以更加开阔的地形条件为特点的格但斯克湾时却表现出一些不足. 相似文献
744.
Sφren Gram Lars Peter Kvist Armando Caseres 《Ambio-人类环境杂志》2001,30(6):365-368
秘鲁亚马孙流域的农民从事农业,同时从天然林,河流和湖泊中获取各种各样的产品,他们多样化的生活方式包括捕鱼,狞猎和采集植物产品.在2个泛滥平原的村庄里,我们已经收集了一年的资料对当地农业经济与为满足生活基本需求和商业贸易的林业经济进行比较.此研究中的林产品包括动物产品(狞猎和捕鱼)和植物产品(木材和非木材).结果表明为了生活需要而获取的林产品尤其是鱼,是当地经济的支柱.获取林产品的日净收入高于种植和非熟练工人正常的日工资收入,这说明在实施任何土地开发利用的决策之前对社会经济情况进行全面的调查研究显得尤为重要.每公顷天然林可获取林产品的价值为平均每年13美元,平均每户可利用的天然林面积为113hm2.如果把农业产出也计算在内的话,每公顷土地的总产值(包括农业和林业)就上升到每年21美元. 相似文献
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750.
Serge Eric Attignon Thibault Lachat Brice Sinsin Peter Nagel Ralf Peveling 《Agriculture, ecosystems & environment》2005,110(3-4):318-326
Responses of termite assemblages to the conversion of semi-deciduous forest into teak plantations were studied in the Lama Forest Reserve in Benin, West Africa. Four belt transect surveys were run in each of the two forest types, adopting a modified termite diversity assessment protocol. Termite assemblages were remarkably species-poor in both forest types, with only 19 species encountered altogether. The low species richness was due to the rarity of soil-feeders of the soil/humus interface and the absence of true soil-feeders in the compact vertisol soil. Species richness was significantly higher in semi-deciduous forest than in teak plantations, but termite encounters were significantly lower. Termite assemblage and feeding group structure differed significantly among forest types. Wood-feeders were recorded only in semi-deciduous forest. In contrast, fungus-growers were more species-rich and about four times more abundant in teak plantations, mainly due to one Ancistrotermes species. The humification score, which depicts the position of termite assemblages along a gradient of increasing humification of their food substrate, was significantly higher in teak plantations, due to the absence of wood-feeders and the preponderance of fungus-growers. Combined principal components and multiple regression analysis identified two significant predictors of termite assemblages, soil water content and leaf litter biomass. The abundance of fungus-growers in teak plantations seemed to be mainly related to the high leaf litter biomass. Indirect evidence also suggests that lower predation pressure by ants on termites in teak plantations may have contributed to the abundance of termites. 相似文献